Grinding apparatus for paste-like or dough-like material



E. BEYELER Dec. 20, 1966 GRINDING APPARATUS FOR PASTE-LIKE OR DOUGH-LIKEMATERIAL Filed July 13, 1964 Inventar= United States Patent 3,292,869GRINDING APPARATUS FOR PASTE-LIKE 0R DOUGH-LIKE MATERIAL Ernst Beyeler,Beuthener Str. 25, Aalen, Wurttemberg, Germany Filed July 13, 1964, Ser.No. 382,327 Claims priority, application Germany, July 12, 1963,

4 Claims. (Cl. 24137) The present invention relates to a grindingapparatus for paste-like or dough-like material having at least twooppositely disposed and'adjustable grinding rollers.

For the fine grinding of paste-like or dough-like material, amongothers, a rolling mill having two or more rollers is used. The finenessof the material to be obtained is determined, thereby, by the distancebetween each pair of oppositely disposed rollers, whereby the layerthickness corresponds about to the half maximum grain size, since thegrains of the material to be ground are flattened during grinding.

Until now, in order to obtain the desired fineness of the material, thedistance between the rollers has been adjusted, instead of changing theeffective pressure force exerted between the rollers. The material wastested from time to time and then the force was increased or reduced,depending on whether the material was too coarse or too fine. Thismethod is cumbersome and has in addition the drawback, that the rollersmust be observed continuously during their operation, even while theyare idling and, thereby, liable to damage each other.

It is, therefore, one object of the present invention to provide agrinding apparatus for paste-like or dough-like material, wherein, forthe sensing of the thickness of the layer of material adhering to oneroller and passed between the rollers, a mechanical sensing member isradially and adjustably disposed adjacent the one roller and isconnected, by means of a lever transmission enlarging the changes of thelayer thickness, with a transmitter, which upon a deviation of the layerthickness which surpasses the tolerance relative to a given value,operates as adjust-- ment device depending upon the direction of thisdeviation for the change of the distanceof the rollers.

It is another object of the present invention to provide a grindingapparatus for paste-like or dough-like material, wherein immediatelyafter the grinding process the layer thickness is sensed. Then by meansof the lever transmission, the deviations of the layer thickness areincreased and are transmitted to a transmitter, which compares thesedeviations with a given value and, in case of surpassing the tolerance,operates an adjustment device, which changes the distance of therollers. Any changes of the layer thickness, which can be caused, forinstance, by change of the nature of the fed material, as the humiditycontent or due to heat expansion of the rollers, are immediatelyobserved and compensated for.

The apparatus designed in accordance with the present invention isapplicable for very thin layer thicknesses, of the order of a few ,u. Ifby coincidence the distance between the rollers should get so low thatno material can pass any more, this error is immediately observed, andthe distance between the rollers is enlarged again.

Thus, the rollers are properly protected from damage.

It is still another object of the present invention to provide agrinding apparatus for paste-like or dough-like material, wherein,preferably, for the setting of the given value, a setting member for thegiven value is provided, which is adjustable opposite that part of thetransmitter sitting at the end of the lever transmission. By adjustmentof the setting member of the given value, the desired layer thicknesscan be set.

3,292,869 Patented Dec. 20, 1966 The rollers are subjected to wearduring their operation after an appreciable time. The layer thicknesswould, however, increase to the same degree, since the setting member ofthe given value does not adjust the thickness of the layer, rather onlythe outer radius of the layer. The fact that the inner radius of thelayer becomes smaller due to wear of the rollers, is not taken intoconsideration by the apparatus without particular measures. In order toremedy this situation, in accordance with a further development of thepresent invention, the setting member for the given value is adjustablerelative to a scale slide, which in turn is settable for the calibrationof the apparatus jointly with the setting member for the given value. Byadjustment of the scale slide, it is possible to calibrate from time totime the apparatus to the roller diameter which has become smaller dueto wear.

With these and other objects in View, which will become apparent in thefollowing detailed description, the present invention will be clearlyunderstood in connection with the accompanying drawing, in which theonly figure shows schematically an elevation of the grinding apparatus.

A grinding mill, means for feeding the material to be ground thereto anda wiper for removal of the material from the roller are known. Theseparts are, therefore, shown schematically only.

The grinding apparatus comprises an immovably mounted roller 1 and asecond roller 3, which is movable towards the roller 1 from below bymeans of a setting device 5 to the desired distance between the rollers1 and 3. The material to be ground is fed to the roller 3 as a layer 4by any conventional suitable means (not shown) and runs on the rightside of the roller 3, as shown in the drawing, then between the rollers1 and 3, and finally around the faster rotating roller 1 in clockwisedirection to the wiper 7.

A roller 9 is provided, which serves the purpose of sensing the layerthickness, which roller 9 is freely rotatably mounted in a double-armedlever 11 and is designed as a flat disc mounted on a ball bearing (notshown). The left end of this double-armed lever 11 is connected by meansof a link 13 with a lever 15 close to the immovable pivot point of thelatter. Likewise, the end of the lever 15 is connected by means of alink 17 with a lever 19 close to the immovable pivot point of thelatter. Levers and links, respectively, 1119 constitute jointly thelever transmission by which small displacements of the roller 9 relativeto the roller 1 under the influence of the layer thickness deviationsare transformed into comparatively large displacements of the left endof the lever 19. The left end of the lever 19 is formed as a contactindicator 19a. A spring 21, one end of which is secured to the lever 19,maintains the lever transmission in a balance and maintains a slightpressure of the roller 9 to the layer 4 of the material provided on theroller 1.

A slide 25 is vertically adjustable in an immovable frame 23 by means ofa set screw 27. The slide 25 carries a layer thickness scale 29, whichis calibrated in /L. A setting member 33 for the given value is slidablerelative to the scale slide 25 by means of another set screw 31, whichis disposed axially in the scale slide 25. The setting member 33 isdesigned as a small slide, which is guided along the scale slide 25. Thesetting member 33 for the given value carries a scale indictaor 35, aswell as electric contacts or terminals 37 and 39, between which thecontact tongue 19a is disposed to perform a pendulum movementtherebetween.

The contacts 37 and 39 are connected by means of conduits 41 to areversible servo-motor 43. The further electric connections which leadfrom a current source (not shown), on the one hand, to the contacttongue 19a and,

on the other hand, to the serve-motor 43, are not disclosed in thedrawing, since these connections are of conventional nature and notparticular subject matter of the present invention. The servo-motor 43is in driving connection with a control valve 45, which either feedspressure fluid by means of a hydraulic conduit 47 to the hydraulicallyoperating setting device 5, or which releases pressure fiuid therefrom.The control valve 45 is in usual manner in connection with a containerreceiving the pressure medium and with a pump (not shown).

For the setting of the desired layer thickness, the setting member 33for the given value is set by means of the set screw 31 relative to theslide 25, until its pointer 35 points to the desired layer thickness. Ifthe tongue 19a is in the center between the electric contacts 37 and 39,the roller 9 has the set distance from the surface of the roller 1. Thefreedom of movement of the tongue 19a up to the engagement with thecontacts 37 and 39 corresponds with the tolerance. If the layerthickness is too great, the roller 9 and the levers 11, 15 and 19 movein the direction of the arrows indicated in the drawing. The contact 39will then engage the tongue 19a, thereby, closingthe circuit to theservo-motor 43 for operation in such direction, that the control valve45 feeds the pressure medium through the hydraulic conduit 47 to thesetting device 5, so that the roller 3 is lifted and, thereby, the layerthickness is reduced. Due to this adjustment, the roller 9 and thelevers 11, 15 and 19 move in a direction opposite to the arrows shown inthe drawing, so that the contact 39 will be opened again bydisengagement from the contact tongue 19a and the feed of pressuremedium ceases. If the layer thickness is too small, an action inopposite direction takes place.

If the roller diameter changes due to wear, the apparatus can be newlycalibrated in the following manner:

While the roller 1 is free from any material to be ground, the settingmember 33 for the given value is set to a layer thickness zero. Theroller 9 engages the surface of the roller 1. The scale slide 25 is nowset jointly with the setting member 23 of the given value by the setscrew 27 such, that the contact tongue 19a assumes a .position in thecenter between the contacts 37 and 39. The slide 25 remains then in itsposition, while the setting member 33 for the given value is adjusted bymeans of the set screw 31 relative to the slide 25 to the desired layerthickness.

Instead of the provision of electrical contacts 37 and 39, it is alsopossible to provide an arrangement with two light barriers andphotocells, whereby light barriers (not shown) are provided, and alwaysone of the light barriers is interrupted by a complementary designedtongue 19:: upon surpassing the tolerance and, thereby, the servomotor43 is put into operation.

Instead of a hydraulic setting device 5, as shown in the drawing, it isof course also possible to provide a mechanical setting device for theroller 3, which is then directly operated from the servo-motor 43.

While I have disclosed one embodiment of the present invention, it is tobe understood that this embodiment is given by example only and not in alimiting sense, the

scope of the present invention being determined by the objects and theclaims.

I claim:

1. A grinding apparatus for paste-like or dough-like material comprisingat least two grinding rollers adjustable realtive to each other andadapted to pass the material to be ground therebetween, said material toform a layer on said one of said rollers receiving said material,

a mechanical sensing member adjustably disposed radially to said one ofsaid rollers for sensing the thickness of said layer of said material,

lever transmitting means operatively connected .with' said mechanicalsensing member and enlarging the changes of thickness of said layersensed by said sensing member,

a setting device supporting and adjusting the distance between the otherof said rollers and said one of said rollers, and means operativelyconnected with said lever transmitting means for operation of saidsetting means in the required direction in response to a surpassing of apredetermined given value of the change of the thickness of said layerof material. 2. The apparatus, as set forth in claim 1, wherein saidmeans for operation of said setting means includes a setting member forsetting said predetermined given value, and

means for adjusting said setting member relative to said,

lever transmitting means. 3. The apparatus, as set forth in claim 2,wherein said setting member includes two oppositely disposed electriccontacts spaced apart from each other,

an end member of said lever transmitting means is mounted to constitutea contact tongue and to perform a pendulum movement between saidelectric References Cited by the Examiner UNITED STATES PATENTS 496,2724/ 1893 Miebach 33 172 2,339,359 1/1944 Shayne et al. 8374 X 2,384,5199/1945 Aller 33172 3,084,314 4/l963 Ziffer 47 X ANDREW R. JUHASZ,Primary Examiner.

1. A GRINDING APPARATUS FOR PASTE-LIKE OR DOUGH-LIKE MATERIAL COMPRISINGAT LEAST TWO GRINDING ROLLERS ADJUSTABLE REALTIVE TO EACH OTHER ANDADAPTED TO PASS THE MATERIAL TO BE GROUND THEREBETWEEN, SAID MATERIAL TOFORM A LAYER ON SAID ONE OF SAID ROLLERS RECEIVING SAID MATERIAL, AMECHANICAL SENSING MEMBER ADJUSTABLY DISPOSED RADIALLY TO SAID ONE OFSAID ROLLERS FOR SENSING THE THICKNESS OF SAID LAYER OF SAID MATERIAL,LEVER TRANSMITTING MEANS OPERATIVELY CONNECTED WITH SAID MECHANICALSENSING MEMBER AND ENLARGING THE CHANGES OF THICKNESS OF SAID LAYERSENSED BY SAID SENSING MEMBER, A SETTING DEVICE SUPPORTING AND ADJUSTINGTHE DISTANCE BETWEEN THE OTHER OF SAID ROLLERS AND SAID ONE OF SAIDROLLERS, AND MEANS OPERATIVELY CONNECTED WITH SAID LEVER TRANSMITTINGMEANS FOR OPERATION OF SAID SETTING MEANS IN THE REQUIRED DIRECTION INRESPONSE TO A SURPASSING OF A PREDETERMINED GIVEN VALUE OF THE CHANGE OFTHE THICKNESS OF SAID LAYER OF MATERIAL.